A sintered bearing is a porous member having innumerable internal pores, and is usually used in the condition that the internal pores are immersed with a lubricant fluid (for example, lubricating oil). In this case, as the sintered bearing and a shaft inserted on the inner periphery of the sintered bearing relatively rotate, the lubricating oil retained in the internal pores of the sintered bearing seeps onto the inner peripheral surface (bearing surface) of the sintered bearing as the temperature rises. The seeped lubricating oil forms an oil film in the bearing gap between the bearing surface of the sintered bearing and the outer peripheral surface of the shaft, and the shaft is relatively rotatably supported.
For example, Patent Document 1 below describes an iron-copper-based sintered bearing which is mainly composed of iron and copper, and which is obtained by compacting and sintering a copper-coated iron powder, in which an iron powder is coated with copper in an amount of greater than or equal to 10 mass % and less than 30 mass %, and the granularity is less than or equal to 80 mesh.